Placing an ensemble of pressure sensors for leak
detection in water distribution networks under
measurement uncertainty
Ehsan Raei, M. Ehsan Shafiee, Mohammad Reza Nikoo
and Emily Berglund
ABSTRACT
Large volumes of water are wasted through leakage in water distribution networks, and early
detection of leakages is important to minimize lost water. Pressure sensors can be placed in a
network to detect changes in pressure that indicate the presence of a new leak. This study presents
a new approach for placing a set of pressure sensors by creating a list of candidate locations based
on sensitivity to leaks that are simulated at all potential nodes in a network. The selection of a set of
sensors is explored for two objectives, which are the minimization of the number of sensors and
the time of detection. The non-dominated sorting genetic algorithm (NSGA-II) is used to explore
trade-offs between these objectives. The effect of measurement uncertainty on the selection of
sensor locations is explored by identifying alternative non-dominated fronts for different values
for sensor error. The evolutionary algorithm-based approach is applied and demonstrated for the
C-Town water network.
Ehsan Raei
Mohammad Reza Nikoo
Department of Civil and Environmental
Engineering,
Shiraz University,
Shiraz,
Iran
M. Ehsan Shafiee
Sensus USA Inc.,
639 Davis Dr., Morrisville, NC,
USA
Emily Berglund (corresponding author)
Department of Civil, Construction, and
Environmental Engineering,
North Carolina State University,
2501 Stinson Dr., Mann Hall, Campus Box 7908,
27695, Raleigh, NC,
USA
E-mail: emily_berglund@ncsu.edu
Key words | genetic algorithm, leak detection, NSGA-II, pressure sensors, uncertainty
INTRODUCTION
Water distribution networks are designed and operated to
reliably deliver water to meet demands while maintaining
pressures throughout a network. Leakages cause failures
in delivering water reliably, and water loss reduction is a
critical goal for managing infrastructure and water
resources. In the UK, 3,281 mega liters (10
6
) of water were
reported as wasted due to leaks in pipelines during 2009–
2011, and some utilities in the USA report 15% of water
lost each year (Sadeghioon et al. ). Leakages contribute
to failures in infrastructure and lead to economic impacts
through lost revenue, excessive power consumption, and
costs that are passed on to end users (Ponce et al. ).
While the immediate effect of a new leak is the propagation
of a transient wave in the pipe network, the transient wave
disappears quickly after the event (Duan a, b), and
the permanent effect of a leakage is a readjustment of press-
ures in nearby pipes (Filion & Karney ). The combined
effect of multiple leakages is a substantial pressure drop in a
water network, which causes consumer complaints and low
water quality issues. To address loss of performance, utilities
apply strategies to increase pressures in affected areas, such
as managing pressure through tight control over isolated
sub-sectors, or district metered areas (DMAs) (Perelman
et al. ; Laucelli et al. ; Samir et al. ). Utilities
may add booster pumps, tune pressure reducing valves to
deliver higher pressures, close selected loops to deliver
water along shorter paths, and reschedule pump operations
to increase pressure in affected areas. Water utilities have
also begun to invest in tools for detecting leakages to more
effectively manage water losses (Mutikanga et al. ).
223 © IWA Publishing 2019 Journal of Hydroinformatics | 21.2 | 2019
doi: 10.2166/hydro.2018.032
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